Modern wireless mobile communication systems present two significant characteristics: first, a high-speed broadband, for example, the bandwidth of the Fourth Generation wireless mobile communication system can reach 100 MHz and a downlink speed of up to 1 Gbps; and second, mobile interconnection is adopted, thereby promoting emerging services such as mobile internet access, mobile phone video-on-demand, online navigation and the like. These two characteristics propose relatively high requirements for a wireless mobile communication technology. Such requirements mainly include: ultrahigh speed wireless transmission, inter-region interference suppression, mobile reliable signal transmission, distributed/centralized signal processing and the like. To satisfy the development requirements above, in a future, more enhanced Fourth Generation (4G) or Fifth Generation (5G) wireless mobile communication system, various corresponding key technologies will begin to be proposed and demonstrated, arousing the attention of researchers in the field.
In October 2007, the International Telecommunication Union (ITU) approved the Worldwide Interoperability for Microwave Access (WiMax) system to become the fourth 3G system standard. In order to respond to the challenge of wireless IP technical flow represented by a wireless local area network and WiMax, since 2005, the Third Generation Partnership Project (3GPP) organization has started to carry out brand-new system upgrade, i.e., standardization of a Long Term Evolution (LTE) system. It is a quasi fourth generation system based on an Orthogonal Frequency Division Multiplexing (OFDM) technology, the first edition of the quasi fourth generation system was released early in 2009, and the quasi 4G system began to be commercially available in succession all over the world in 2010. Meanwhile, the 3GPP organization started standardization customization of the Fourth Generation (4G) wireless mobile communication system the first half of 2008. This system is called a Long Term Evolution Advanced (LTE-A) system. The key standardization document of the physical layer process of the system was completed early in 2011. In November 2011, the ITU organization officially announced, in Chongqing China, that the LTE-A system and the WiMax system were two official standards of the 4G system. At present, the commercial process of the LTE-A system is being developed gradually worldwide.
According to the challenges in the next 10 years, the following development requirements are substantially provided for an enhanced 4G wireless mobile communication system.                A higher wireless broadband speed is required, and optimization of local cell hot spot regions is emphasized.        The user experience is further improved, particularly it is necessary to optimize communication services of cell boundary regions.        In view of it being impossible to expand clear bands spectra 1000 times, it is necessary to continue researching a new technology capable of improving spectrum band utilization efficiency.        High-frequency bands spectra (5 GHz or greater) will certainly come into use to obtain a larger communication bandwidth.        Existing networks (2G/3G/4G, WLAN, WiMax, etc.) cooperate to share data traffic.        Different services, applications and service are specifically optimized.        A system capability of supporting large-scale machine communications is supported.        Network planning and distribution are flexible, smart and inexpensive.        A solution is designed to save the power consumption of a network and the battery consumption of user equipment.        
At present, in the traditional 3GPP LTE system, whether the uplink transmission or downlink transmission can support, at most, the aggregation of 5 Component Carriers (CCs), and if each component carrier is up to 20 MHz, the user equipment can simultaneously support, at most, the uplink and downlink transmission of 100 MHz. With the growing demand of data traffic, it has been difficult to meet the future need of 100 MHz transmission bandwidth. A new research subject, i.e. research of LTE carrier aggregation enhancement beyond 5 carriers (RP-142286) was discussed at the 66th 3GPP RAN Conference, which mainly aimed at researching aggregation technology supporting up to 32 component carriers (CC) during uplink and downlink so as to increase the transmission speed.
For this purpose, a key problem exists in the system design, i.e., how the user equipment feeds back Hybrid Automatic Retransmission Request (HARQ) information transmitted by downlink data in an uplink channel. At present, the user equipment in the system, in a carrier aggregation scene, adopts a Physical Uplink Control Channel (PUCCH) format 3 to transmit Hybrid Automatic Retransmission Request (HARQ) feedback corresponding to Physical Downlink Shared Channel (PDSCH) transmission on 8 carrier components at most, and one transmission using the PUCCH format 3 needs to occupy two uplink Physical Resource Blocks (PRBs). However, according to requirements of a current Rel-13 CA, the PUCCH format 3 cannot simultaneously transmit HARQ feedback information of 32 downlink CCs.